The recently reported destruction of the coral reefs of Sarangani Bay due to the construction of the unloading pier for the region’s coal-fired power plant has raised the question of how seriously has the destruction of the reefs affected the ability of the coastal town of Maasim in Sarangani from undertaking effective disaster risk reduction and climate change adaptation efforts in the long run?

It seems the answer is yes, it’s pretty serious, since coral reefs protect the coasts in the following ways:

1. They reduce the energy of the wave

A very recent study in the science journal Nature Communications that came out this month of May showed that coral reefs provide substantial protection against natural hazards by reducing wave energy by an average of 97% that would otherwise impact shorelines. Reef crests alone dissipate most of this energy (86%). This ability to reduce the energy of the wave is important since, as Michael W. Beck and Christine C. Shepard (2012) illustrate, in many places, these reefs serve as breakwaters and are the first line of coastal defense for hazards associated with waves, erosion and flooding.

Nature Conservancy (2012) in a briefer for its project on coastal resilience state that in coastal areas where wave energy is lower, mangroves can grow and further stabilize shorelines, reduce erosion, and provide nursery habitat for fish, shrimp and crab.

2. They reduce the height of the wave

The same study reported in Nature Communications also looked at the effect of coral reefs on wave heights and found that, as expounded by the up-and-coming explanatory website Vox, healthy coral reefs offer a surprising amount of protection against storms –reducing the height of waves by 51 or 75%. By comparison, the artificial breakwater systems used in places like Hawaii or Sri Lanka tend to reduce wave height by 30 to 70%, on average. Just imagine how typhoon Yolanda (international name : Haiyan) which was tracked by NASA satellites in its early stages to have generated 50-foot waves as it moved towards the Philippines, would have impacted coastal areas with a good set of coral reef cover, the storm surges that had happened would not have been as severe.

3. They control the erosion of the beachfront

Jeffrey Wielgus, et.al (2010) did a study in the Dominican Republic which indicated that, In addition to providing a source of sand, coral reefs control the rates of beach erosion by reducing the energy of incoming oceanic waves. Other natural features of the coast also play important protective roles. Sand dunes and their associated vegetation control the erosive impact of wind, while mangroves stabilize the shoreline and provide additional protection from waves. The energy carried by waves is related to the water depth, so rising sea levels, a consequence of climate change, also contribute to beach erosion by increasing the energy of waves reaching the shoreline. If the ability of coral reefs or sand dunes to control erosion is impaired, beaches will suffer a net loss of sand.

4. Coral reefs provide livelihoods to the communities near the coasts

Coastal communities largely depend on the seas for their livelihood either by way of fishing, tourism and recreation and other ways of earning off the marine ecosystem. This is validated by a study done in Caribbean coral reefs by University of Queensland researchers led by Dr. Alice Rogers which found that a complete loss of reef complexity would lead to more than a three-fold decrease in the production of large-bodied reef fish.

“That means three-times less potential catch for a fishery, which would have a huge impact on food security and peoples’ livelihoods”, said Dr Rogers.

The researchers showed that more complex reef habitats provided refuge to vulnerable prey organisms, including juvenile and small-bodied species of fish. When this complexity is lost the dynamics of the reef community change, leading to fewer small and medium-bodied fish, and fewer fish overall.